Salt taste responses of mouse chorda tympani neurons: evidence for existence of two different amiloride-sensitive receptor components for NaCl with different temperature dependencies

1996 ◽  
Vol 76 (5) ◽  
pp. 3550-3554 ◽  
Author(s):  
Y. Ninomiya
Keyword(s):  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Inhibitory Effects ◽  
Strong Suppression ◽  
Salt Taste ◽  
Single Fibers ◽  
Different Temperatures ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Mouse Taste

1. Inhibitory effects of amiloride on salt responses of single fibers of the chorda tympani nerve of the C57BL/6 strain of mice were examined at two different temperatures (approximately 12 and 24 degrees C). 2. Of 36 single fibers that responded to NaCl, 20 fibers showed strong suppression of responses to NaCl actuated by lingual treatment with amiloride (amiloride-sensitive fibers), whereas the remaining 16 fibers showed no such amiloride inhibition (amiloride-insensitive fibers). 3. Twenty amiloride-sensitive fibers were further classified into two subgroups according to the temperature dependency of their NaCl responses. In 15 of 20 fibers, amiloride-inhibitable NaCl responses were larger at 24 degrees C than at 12 degrees C, whereas the reverse was true for the remaining 5 fibers. All amiloride-insensitive fibers showed smaller responses to NaCl at 12 degrees C. 4. These results suggest that there exist two different amiloride-sensitive receptor components for NaCl with different temperature dependencies in mouse taste cells: one is more sensitive to NaCl at the higher temperature, and the other is more sensitive at the lower temperature.

Sweet Taste Responses of Mouse Chorda Tympani Neurons: Existence of Gurmarin-Sensitive and -Insensitive Receptor Components

1999 ◽  
Vol 81 (6) ◽  
pp. 3087-3091 ◽  
Author(s):  
Yuzo Ninomiya ◽  
Toshiaki Imoto ◽  
Tadataka Sugimura
Keyword(s):  
Sweet Taste ◽  
The Other ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Inhibitory Effects ◽  
Single Fibers ◽  
Taste Cells ◽  
C57bl Mice ◽  
Mouse Taste

Sweet taste responses of mouse chorda tympani neurons: existence of gurmarin-sensitive and -insensitive receptor components. Inhibitory effects of gurmarin (gur) on responses to sucrose and other sweeteners of single fibers of the chorda tympani nerve in C57BL mice were examined. Of 30 single fibers that strongly responded to 0.5 M sucrose but were not or to lesser extent responsive to 0.1 M NaCl, 0.01 M HCl, and 0.02 M quinine HCl (sucrose-best fibers), 16 fibers showed large suppression of responses to sucrose and other sweeteners by lingual treatment with 4.8 μM (∼20 μg/ml) gur (suppressed to 4–52% of control: gur-sensitive fibers), whereas the remaining 14 fibers showed no such gur inhibition (77–106% of control: gur-insensitive fibers). In gur-sensitive fibers, responses to sucrose inhibited by gur recovered to ∼70% of control responses after rinsing the tongue with 15 mM β-cyclodextrin and were almost abolished by further treatment with 2% pronase. In gur-insensitive fibers, sucrose responses were not inhibited by gur, but were largely suppressed by pronase. These results suggest existence of two different receptor components for sweeteners with different susceptibilities to gur in mouse taste cells, one gur sensitive and the other gur insensitive. Taste cells possessing each component may be specifically innervated by a particular type of chorda tympani neurons.

scholarly journals Synthesis of Fe3O4 and Fe2O3 nanoparticles using hybrid electrochemical-thermal method

2020 ◽  
Vol 55 (3) ◽  
pp. 221-228
Author(s):  
HA Simol ◽  
R Sultana ◽  
M Y A Mollah ◽  
MS Miran
Keyword(s):  
Iron Oxide ◽  
Total Pore Volume ◽  
Thermal Method ◽  
Prepared Compound ◽  
Xrd Pattern ◽  
Spectral Techniques ◽  
Different Temperatures ◽  
Ft Ir ◽  
Higher Temperature ◽  
Lower Temperature

Nanocrystalline Fe3O4 and Fe2O3 particles were successfully synthesized by an innovative hybrid electrochemical-thermal method. The as-prepared compound was calcined for an hour from 100 to 600oC temperatures. The crystallinity, morphology and chemical state of the synthesized powders were characterized by XRD, TG-DTA, SEM/EDS, FT-IR, and UV–Vis spectral techniques after calcinations. The Brunauer–Emmett–Teller (BET) plots confirmed that iron oxide nanoparticles (NPs) calcined at 400oC has a surface area of 18.28 m2 g-1 with a total pore volume of 0.2064 cc g-1. From XRD pattern it is revealed that the precursor calcined at lower temperature (100-400oC) correspond to Fe3O4,while the ones calcined at higher temperature follow Fe2O3 pattern. The morphology of iron oxide NPs calcined at different temperatures were studied with scanning electron microscope (SEM) and exhibits spherical shaped geometries with average diameters of 80-150nm. Bangladesh J. Sci. Ind. Res.55(3), 221-228, 2020

Salt taste discrimination after bilateral section of the chorda tympani or glossopharyngeal nerves

1992 ◽  
Vol 263 (1) ◽  
pp. R169-R176 ◽  
Author(s):  
A. C. Spector ◽  
H. J. Grill
Keyword(s):  
Discrimination Performance ◽  
Taste Buds ◽  
Glossopharyngeal Nerve ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Salt Taste ◽  
Critical Elements ◽  
Electrophysiological Findings ◽  
Taste Discrimination ◽  
Salt Taste Discrimination

Gustatory deafferentation of the anterior tongue by bilateral section of the chorda tympani nerve, which removes only 15% of the total taste buds in the rat, severely impaired the rat's ability to discriminate NaCl from KCl. The discrimination deficit was selective. Denervated rats were able to discriminate sucrose from quinine. Despite eliminating four times as many taste buds by bilateral section of the glossopharyngeal nerve, posterior lingual deafferentation had no effect on NaCl vs. KCl discrimination performance. Collectively, these data suggest that afferents in the chorda tympani nerve provide the highest degree of disparity between the peripheral signals representing NaCl and KCl. Electrophysiological findings of others implicate the sodium-specific afferents that appear to exclusively exist in the chorda tympani nerve as the critical elements subserving the NaCl vs. KCl discrimination.

scholarly journals Effects of voltage perturbation of the lingual receptive field on chorda tympani responses to Na+ and K+ salts in the rat: implications for gustatory transduction.

1994 ◽  
Vol 104 (5) ◽  
pp. 885-907 ◽  
Author(s):  
Q Ye ◽  
G L Heck ◽  
J A DeSimone
Keyword(s):  
Receptive Field ◽  
Voltage Clamp ◽  
Maximal Response ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Salt Taste ◽  
Negative Voltage ◽  
Voltage Clamp Condition ◽  
Taste Cells ◽  
Clamp Condition

Taste sensory responses from the chorda tympani nerve of the rat were recorded with the lingual receptive field under current or voltage clamp. Consistent with previous results (Ye, Q., G. L. Heck, and J. A. DeSimone. 1993. Journal of Neurophysiology. 70:167-178), responses to NaCl were highly sensitive to lingual voltage clamp condition. This can be attributed to changes in the electrochemical driving force for Na+ ions through apical membrane transducer channels in taste cells. In contrast, responses to KCl over the concentration range 50-500 mM were insensitive to the voltage clamp condition of the receptive field. These results indicate the absence of K+ conductances comparable to those for Na+ in the apical membranes of taste cells. This was supported by the strong anion dependence of K salt responses. At zero current clamp, the potassium gluconate (KGlu) threshold was > 250 mM, and onset kinetics were slow (12 s to reach half-maximal response). Faster onset kinetics and larger responses to KGlu occurred at negative voltage clamp (-50 mV). This indicates that when K+ ion is transported as a current, and thereby uncoupled from gluconate mobility, its rate of delivery to the K+ taste transducer increases. Analysis of conductances shows that the paracellular pathway in the lingual epithelium is 28 times more permeable to KCl than to KGlu. Responses to KGlu under negative voltage clamp were not affected by agents that are K+ channel blockers in other systems. The results indicate that K salt taste transduction is under paracellular diffusion control, which limits chemoreception efficiency. We conclude that rat K salt taste occurs by means of a subtight junctional transducer for K+ ions with access limited by anion mobility. The data suggest that this transducer is not cation selective which also accounts for the voltage and amiloride insensitive part of the response to NaCl.

Enhancement of gustatory nerve fibers to NaCl and formation of ion channels by commercial novobiocin

1994 ◽  
Vol 266 (5) ◽  
pp. C1165-C1172 ◽  
Author(s):  
A. M. Feigin ◽  
Y. Ninomiya ◽  
S. M. Bezrukov ◽  
B. P. Bryant ◽  
P. A. Moore ◽  
...  
Keyword(s):  
Ion Channels ◽  
Lipid Bilayers ◽  
Neutral Lipids ◽  
Nerve Fibers ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Salt Taste ◽  
Cation Selectivity ◽  
Taste Response ◽  
Gustatory Nerve

Single fibers of the rat chorda tympani nerve were used to study the mechanism of action of the antibiotic novobiocin on salt taste transduction. In the rat, novobiocin selectively enhanced the responses of sodium-specific and amiloride-sensitive chorda tympani nerve fibers (N type) without affecting more broadly responsive cation-sensitive and amiloride-insensitive fibers (E type). In the presence of amiloride, novobiocin was ineffective at enhancing the response of N-type fibers toward sodium chloride. Novobiocin also increased the conductance of bilayers formed from neutral lipids by forming nonrectifying ion channels with low conductance (approximately 7 pS in 110 mM NaCl), long open times (several seconds and longer), and high cation selectivity. Amiloride did not alter either the conductance or kinetics of these novobiocin channels. These observations suggest that even though novobiocin is able to form cation channels in lipid bilayers, and possibly in cell membranes as well, its action on the salt-taste response is through modulation of existing amiloride-sensitive sodium channels.

scholarly journals Contribution of the TRPV1 channel to salt taste quality in mice as assessed by conditioned taste aversion generalization and chorda tympani nerve responses

2012 ◽  
Vol 303 (11) ◽  
pp. R1195-R1205 ◽  
Author(s):  
Kimberly R. Smith ◽  
Yada Treesukosol ◽  
A. Brennan Paedae ◽  
Robert J. Contreras ◽  
Alan C. Spector
Keyword(s):  
Citric Acid ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Taste Quality ◽  
Transient Receptor Potential Vanilloid ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Trpv1 Channel ◽  
Salt Taste ◽  
Transient Receptor

In rodents, at least two transduction mechanisms are involved in salt taste: 1) the sodium-selective epithelial sodium channel, blocked by topical amiloride administration, and 2) one or more amiloride-insensitive cation-nonselective pathways. Whereas electrophysiological evidence from the chorda tympani nerve (CT) has implicated the transient receptor potential vanilloid-1 (TRPV1) channel as a major component of amiloride-insensitive salt taste transduction, behavioral results have provided only equivocal support. Using a brief-access taste test, we examined generalization profiles of water-deprived C57BL/6J (WT) and TRPV1 knockout (KO) mice conditioned (via LiCl injection) to avoid 100 μM amiloride-prepared 0.25 M NaCl and tested with 0.25 M NaCl, sodium gluconate, KCl, NH4Cl, 6.625 mM citric acid, 0.15 mM quinine, and 0.5 M sucrose. Both LiCl-injected WT and TRPV1 KO groups learned to avoid NaCl+amiloride relative to controls, but their generalization profiles did not differ; LiCl-injected mice avoided the nonsodium salts and quinine suggesting that a TRPV1-independent pathway contributes to the taste quality of the amiloride-insensitive portion of the NaCl signal. Repeating the experiment but doubling all stimulus concentrations revealed a difference in generalization profiles between genotypes. While both LiCl-injected groups avoided the nonsodium salts and quinine, only WT mice avoided the sodium salts and citric acid. CT responses to these stimuli and a concentration series of NaCl and KCl with and without amiloride did not differ between genotypes. Thus, in our study, TRPV1 did not appear to contribute to sodium salt perception based on gustatory signals, at least in the CT, but may have contributed to the oral somatosensory features of sodium.

scholarly journals Effect of Chorda Tympani Nerve Transection on Salt Taste Perception in Mice

2011 ◽  
Vol 36 (9) ◽  
pp. 811-819 ◽  
Author(s):  
G. J. Golden ◽  
Y. Ishiwatari ◽  
M. L. Theodorides ◽  
A. A. Bachmanov
Keyword(s):  
Taste Perception ◽  
Chorda Tympani ◽  
Nerve Transection ◽  
Chorda Tympani Nerve ◽  
Salt Taste

Gurmarin inhibition of sweet taste responses in mice

1995 ◽  
Vol 268 (4) ◽  
pp. R1019-R1025 ◽  
Author(s):  
Y. Ninomiya ◽  
T. Imoto
Keyword(s):  
Sweet Taste ◽  
Suppressive Effect ◽  
Taste Receptors ◽  
Gymnema Sylvestre ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Inhibitory Effects ◽  
Sweet Taste Receptors ◽  
Before And After ◽  
C57bl Mice

The inhibitory effects of gurmarin (a peptide isolated from the leaves of Gymnema sylvestre) on sweet taste responses were studied by examining the chorda tympani nerve responses to various taste substances before and after lingual treatment with gurmarin in C57BL and BALB mice. Treatment with gurmarin at 3 micrograms/ml or more selectively suppressed responses to sucrose without affecting responses to NaCl, HCl, and quinine in C57BL mice, whereas gurmarin at 100 micrograms/ml did not significantly suppress sucrose responses in BALB mice. Responses to various sweet substances in C57BL mice decreased to approximately 45-75% of control after gurmarin, and the suppressive effect of gurmarin was reversible. The profile of the residual responses of C57BL mice to various sweeteners after gurmarin was almost identical to that of BALB mice, which was hardly affected by gurmarin. These results strongly suggest that there are at least two types of sweet taste receptors in mice, gurmarin-sensitive and -insensitive. Probably, C57BL and BALB mice share an identical gurmarin-insensitive receptor, and C57BL mice also have a gurmarin-sensitive receptor.

scholarly journals THE INFLUENCE OF AGE OF HOST AND TEMPERATURE OF INCUBATION ON INFECTION OF THE CHICK EMBRYO WITH VESICULAR STOMATITIS VIRUS

1943 ◽  
Vol 78 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Björn Sigurdsson
Keyword(s):  
Vesicular Stomatitis Virus ◽  
Virus Titer ◽  
Growth Curves ◽  
Chick Embryos ◽  
Rate Of Increase ◽  
Cent Mortality ◽  
Different Temperatures ◽  
Vesicular Stomatitis ◽  
Higher Temperature ◽  
Lower Temperature

Chick embryos after 7 days of incubation were found to be much more susceptible to infection with vesicular stomatitis virus than were 10 day embryos. They had a 100 per cent mortality and were very suitable for titrations of the virus. The rate of increase of virus in 7 and 10 day embryos was studied. Two different temperatures of incubation were employed, 35–36°C. and 39–40°C., and the growth curves for the virus under the different conditions are presented. 10 day embryos were highly resistant and at 39–40°C. more than half of them survived. At the lower temperature of incubation, 35–36°C., all 10 day embryos died, but they survived much longer than did 7 day embryos. In the 7 day embryos death occurred after about 12 hours at 39–40°C. and after about 16 hours at 35–36°C., or earlier at the higher temperature. In embryos of both ages the virus titer reached at the higher temperature was only about 1 per cent of that reached at 35–36°C., even in those that died.

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